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A comment on Speeding up SQL queries by orders of magnitude using UNION.

Re:Speeding up SQL queries by orders of magnitude using UNION by tech2 on Saturday March 20, 2021 @04:23PM (#26525833)
Perhaps I'm missing something, but why is query 2's meal_items a left join when the where clause then forces it to act as if it were an inner join? Would changing that have any impact?
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Re:Speeding up SQL queries by orders of magnitude using UNION by Albert_Camus on Saturday March 20, 2021 @06:42PM (#26526611)
Author here, you are indeed correct that Query #2's final join can be an INNER join. However, I just tested it against our test data set and it makes no impact on the performance.
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Re:Speeding up SQL queries by orders of magnitude using UNION by tech2 on Sunday March 21, 2021 @06:42AM (#26529481)
Ah well, thanks for humouring me. Good thing those query optimisers do the right thing on occasion.
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